Union types

[FredericWantiez]

Not sure it's an issue but seems a bit weird to override the deepcopy_types from what the user provides.
On master this produces the wrong result because Ref and Array are not deepcopied anymore

using Libtask

struct DummyType end

function f(start::Int)
    t = [start]
    while true
        produce(t[1])
        t[1] = 1 + t[1]
    end
end

ttask = TapedTask(f, 0; deepcopy_types=DummyType)
println(consume(ttask)) # 0 Correct 

ttask2 = copy(ttask)
println(consume(ttask2)) # 1 Correct

println(consume(ttask)) # 2 Incorrect
println(consume(ttask2)) # 3 Incorrect

Maybe we can assume that Array and Ref would always be deepcopied unless explicitly overloaded in tape_deepcopy ?

[yebai]

I am happy with the proposed change.

Just to clarify, it is not possible to override the copying behaviour for Array and Ref without modifying the global variable BASE_COPY_TYPES? Is that intended?

[FredericWantiez]

Yes, not sure it's the best way but I don't really see a case where we want shallow copied arrays, and we can alsways overload tape_deepcopy(x::Array) explicitly. Happy to change